A giant wildfire raging out of control has grown to nearly 200 square miles and spread into Yosemite National Park, as California Governor Jerry Brown declared a state of emergency for the city of San Francisco 150 miles away because of the threat to the city's utilities.
The fire hit the park at the height of summer season, as officials geared up for a busy holiday weekend. It has closed some backcountry hiking but was not threatening the Yosemite Valley region, one of California's most popular tourist destinations that features such famous sights as the Half Dome and El Capitan rock formations and Bridalveil and Yosemite falls.
The blaze did, however, pose a threat to the lines and stations that pipe power to the city of San Francisco, so Mr Brown, who had declared an emergency for the fire area earlier in the week, made the unusual move of extending the emergency declaration to the city across the state.
San Francisco gets 85 percent of its water from the Yosemite-area Hetch Hetchy reservoir that is about 4 miles from the fire, though that had yet to be affected. But it was forced to shut down two of its three hydroelectric power stations in the area.
The city has so far been able to buy power on the open market and use existing supplies, but further disruptions or damage could have an effect, according to city power officials and the governor's statement.
The declaration frees funding and resources to help the city and makes it eligible for more federal funds to help with power shortages and outages or water problems.
The weeklong blaze on the timbered slopes of the Western Sierra Nevada has spread to 196 square miles and was only 5 percent contained. It continued to grow in several directions, although "most of the fire activity is pushing to the east right into Yosemite," said Daniel Berlant, spokesman for the California Department of Forestry and Fire Protection.
Smoke blowing across the Sierra into the state of Nevada forced officials in several counties to cancel outdoor school activities and issue health advisories, especially for people with respiratory problems.
Authorities urged more evacuations in nearby communities where thousands have already been forced out by flames.
The fire was threatening about 5,500 residences, according to the U.S. Forest Service. The blaze has destroyed four homes and 12 outbuildings in several different areas. More than 2,000 firefighters were on the lines and one sustained a heat-related injury.
While the park remained open, the blaze closed a 4-mile stretch of State Route 120, one of three entrances into Yosemite on the west side. Two other western routes and an eastern route were open.
Within the park, the blaze was burning on about 17 square miles in a remote area around Lake Eleanor, Yosemite spokeswoman Kari Cobb said.
Backcountry permits are required to hike in that area, Cobb said. The park was no longer issuing those and had contacted every person who had received a permit to go there. Two roads into that area were closed and occupants of a campground near the Route 120 west entrance were relocated.
The fire was more than 20 miles from Yosemite Valley and skies there were "crystal clear," Cobb said.
On Friday, officials issued voluntary evacuation advisories for two new towns - Tuolumne City, population 1,800, and Ponderosa Hills, a community of several hundred - which are about five miles from the fire line, Forest Service spokesman Jerry Snyder said.
A mandatory evacuation order remained in effect for part of Pine Mountain Lake, a summer gated community a few miles from the fire.
"It feels a little bit like a war zone, with helicopters flying overhead, bombers dropping retardant and 10 engine companies stationed on our street," said Ken Codeglia, a retired Pine Mountain Lake resident who decided to stay to protect his house with his own hoses and fire retardant system. "But if the fire gets very hot and firefighters evacuate, I will run with them."